France prop Cyril Baille has been ruled out for "five to six weeks" with a right calf injury, the FreRugby Federation (FFR) announced on Monday.
The 44-times capped Toulouse player's participation in the Rugby World Cup which gets underway in less than a month is now in doubt.
Baille, 29, picked up the injury during Saturday's 30-27 warm-up victory for the tournament hosts against Scotland.